Music information resources come in an increasing variety of formats, and can take on a variety of forms derived from the same work. This can make the cataloging of musical resources very complex. There is much discussion in the literature about what constitutes a musical “work.” This discussion enters the philosophical and musicological realm in attempting to define a musical work. For librarians and catalogers, the importance of this discussion comes to bear on the creation of bibliographic records. Key to this discussion is FRBR, which shows great potential to improve bibliographic access and discovery when applied to electronic catalogs, particularly in the music domain where instances of the same work may appear in varying formats. Further analysis is made in the context of FRBR as it was applied in the recent development of the Variations digital music library created at Indiana University.